Novel synthesis of popcorn-like TiO₂ light scatterers using a facile solution method for efficient dye-sensitized solar cells

In this study, a facile solution method is proposed for synthesizing popcorn-like TiO₂ aggregations (P-TiO₂) as the light scatterers in the photoanode of DSSCs. This novel solution method is promising due to the less time and lower temperature required for carrying out the reaction, comparing to those for the conventional hydrothermal synthesis. The P-TiO₂ has the size of 300 nm and is composed of small nanoparticles with the size of 50 nm. Also, different from the common light scatterers, the P-TiO₂ has a special anatase phase which is beneficial for dye adsorption and charge transfer. The highest solar-to-electricity conversion efficiency of 7.56% is obtained for the DSSC with the photoanode composed of the commercial P90 TiO₂ dye-adsorption layer and the P-TiO₂ light scattering layer, due to the large surface area, highly active anatase nature, and the excellent light scattering ability for the home-made P-TiO₂. The results suggest that the photovoltaic performance of DSSCs can be efficiently improved by carefully designing the morphology of the TiO₂ nanostructure in the photoanode with large surface area and unique configuration to confine the incident light in the electrode for longer time.